Active IQ Level 2 Certificate in Fitness Instructing (Children) (sample manual)

Diffusion is the
movement of a gas,
from an area of high
concentration, to an
area of low
concentration
Inhalation
Exhalation
Movement of the diaphragm
Costal breathing is a shallow pattern of breathing through the chest and involves the
contraction of the external intercostal muscles (Tortora and Grabowski, 2003).
Diaphragmatic breathing is a deeper method of breathing, through the outward
distension of the abdomen and involving the contraction and lowering of the
diaphragm (Tortora and Grabowski, 2003). Diaphragmatic breathing is promoted to
aid relaxation in activities like yoga, and is linked with improved health (Yeufang,
1996).
Expansion of the rib cage provides an additional increase in chest cavity size. This
should only be required during times of laboured breathing, such as moderate or
high intensity aerobic exercise.
The exchange of gases
O 2
is pulled down the bronchi and bronchioles into the alveoli, by negative pressure,
as described above, but also because it flows down a concentration gradient.
Diffusion is the movement of a gas, from an area of high concentration, to an area
of low concentration. The concentration of O 2
decreases between the mouth and the
lungs, thus the gas flows in this direction. CO 2
flows in the opposite direction for the
same reason. Once the O 2
gets into the alveoli (the air sacs), it will continue to follow
this concentration gradient and will diffuse into the bloodstream. The alveoli have
minute capillaries running over and around them. Both the alveolar walls and the
capillary walls are so thin that they allow gases to pass through them. O 2
passes into
the blood and at the same time, CO 2
passes back into the lungs to be exhaled.
Capillaries
Alveoli
The O 2
binds to the haemoglobin (Hb - the protein that
carries O 2
, CO 2
and carbon monoxide in the blood) in the
red blood cells (RBCs). At the same time CO 2
dissociates
from the haemoglobin and diffuses from the blood into
the lungs. The red blood cells are then pumped within the
blood, via the pulmonary vein, towards the heart. This
constant flow of blood past the alveoli allows the high
concentration gradient to be maintained.
Alveoli
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Level 2 Certificate in Fitness Instructing - MANUAL